Boiler pressure control apparatus



Nov. V16 1937. J. B. SNYDER I BOILER PRESSURE CONTROL APPARATUS Filed March 23, 1956 w H w. M 7 m a, A 5 ll s w M 0 7 3/ o 3 H n SUPPLY To AIR Moron J65 5. Snyder- I V Patented Nov. 16, 1937 UNITED STATES PAT NT OFFICE 2 Claims.

'This invention relates to pressure control de-,

vices and especially to devices adapted to automatically keep the pressure of a .boiler at a uniform figure by controlling the draft of the "boiler.

It has been the practice to attempt to control the steam pressure of the boiler by causing a pressure-controlled apparatus to itself actuate the boiler damper, whereby the draft is cone.

trolled, but'it is evident that, in such a case, the 10 only actuating force would be the diiference. of.

pressure between the balanced or neutral condition of the instrument and the subnormal pressure thereof at the time, in other'words, when the normal pressure is supposed to be say 8 then only one pound is available to actuate the damper. For this reason such controls are of very little value in low' pressure boilers, such as U are used in many heating plants.

devised the following described mechanisms, the primary object being to provide means whereby the boiler draft may be operated by an indeA ard mechanism at present in use, with but little I alteration thereto.

I attain these and other objects by the mechanisms, devices and arrangements illustrated in the accompanying drawing, in which- Fig. 1 is a front elevation of a boiler equipped with my apparatus, showing the parts in their normal positions when the pressure is at normal; Fig. 2 is a longitudinal section of the air motor which actuates the boiler damper, showing it in the act of opening, or holding open, the damper to increase the draft through the boiler; Fig. 3 is a side elevation of my improved means for controlling the air motor, parts being broken away to reveal the construction and showing the position of the parts when the boiler is below its normal pressure; and Fig. 4 is a similar view of .a modified form of such apparatus, showing the parts in the positions taken thereby when the pressure in the boiler is normal.

Similar numerals of reference refer to similar parts throughout the several views.

pounds in the boiler and it drops to ,7 pounds,

In order to overcome this objection I have a quarter of an ounce will cause the damper to Referring to the drawing it will be seen that the boiler I is provided with a draft control or damper 2, of the usual form, adapted to be opened by being raised.

Pressure-sensitive apparatus The steam from the boiler enters the bellows chamber 3 of the usual construction and containing a metallic bellows 4 (Fig. 3) therein, said bellows registering by its upward movement the pressure within the boiler l. The movement of the bellows' l is communicated to a rocker 5, pivot at 6 to the upper side of the chamber 3, and this rocker 5 is provided with an arm 1 on which a weight 8 is adjustably mounted to counteract the action of the steam pressure on the bellows 4. The weight 8 is adjusted so that it is raised by the pressure in the boiler when such pressure has reached its desired predetermined normal. The arm 'i operates between two adjustable stops 9 and II]. The rocker 5 is provided with an extension H, which engages the air-control apparatus, as hereinafter de-.

scribed. Az'r motor Referring, now, to Fig. 2, the air motor comprises a dish [2, having a rubber or otherwise flexible diaphragm l3 secured thereto; a supply of compressed air being admitted to or released from the space between the dish I2 and the diaphragm [3 by means of the pipe l4. A saucer IE rides on the rubber diaphragm l3 and is pivotal- 1 1y connected to an arm l6, pivoted at I! to the air motor frame. This arm I6 is connected at. one end to the damper} by means of a chain I8, and the action of the air under the diaphragm i3 is opposed by a compression spring l9 mounted between the other end of the arm l6 and the airmotor frame. The upward swing of the arm [6 is limited by the adjustable stop 20.

Air control apparatus This apparatus comprises a main body 22 having a cavity divided, by a wall 23 and a rubber diaphragm 24, into three chambers 25, 26 and 21.

The wall 23 has a central hole 28 therethrough,

said hole 28 providing a seat for the floating valve 29. The valve 29 is secured to and passes ,forms the outer closure of the chamber 21, and

has a stem which passes loosely through the hole 28 in the wall 23. The valve 29 has a central hole 35 passing entirely through it and the said stem. The inner orifice of the hole 3| is adapted to be engaged and closed by the first said rubber by a weighted arm 39 as showiiforbyany other equivalent structure. The end of the" abovedescribed extension H on the rocker 5 is hooked to engage the said finger 3'7to' move"it'away from the orifice 36 when the pressure in the boiler is raised to normal and releases the said finger 31 to close the saidorifice 36 'whenjthe pressure is 'slightly'below normal. It will be un; derstood that the by-passag's 33 and '35and the Orifice 36 are of very smalFdiameter'si Variation Referring now to Fig. 4-it will, be seen that the' intermediate finger 3], above described, is dispensed with in this alternate construction,

the extension H acting" directly on the "orifice '35 tobp'en or close it in similar manner as" above describedQ Operation 1 Theeefien. m pp atus i i ly described as ielleue=-When t e boi e r su e is rmal (Figs. l and fl), the compressed air travels rihe ipe 47! and th ss ge: 531mm theorembutea nete ease h refrom h ou h the valve seat in the wall 23 and escapes or leaks hr u h he brr sa h mb r 25;, biz-passage if-Land the open orifice 36, while whatever airr n'ay be in the air motor escapes from be tween the dish l2 and the diaphragm I3 by the pipe [4, passage 34, chamber 26 and hole 3| through the valve 29; the rubber diaphragm 24}, being tinder substantially equal pressure'oh both sides, is straight" and out of contact with the valve 29. I But, the moment that the orifice 36 1 isclosed by" the finger ii'ljorthe extension H,

the ressure in the chamber 25 is built upf thus' bulging t diaphragm" zeiaod" c si t e time 3 i an n the-valve to overlie-e1 velv seatinthe wall 23' (Fig. 3), thus permitting the" dirf'ct'jairpressure to pass from the pipe "2 1 to e eam -f 1P? he P315835? 3 em s" o 2 ,099,239 V V a through the hole 28 in the wall 23, into the chamber 26, thence by the passage 3% and the saucer l and arm 16, and the damper 2 of the boiler. As soon as the boiler'pressure is built up to normaLithe finger 3'1, or the extension H, opens the leakage orifice 36 allowing the escape of the air pressure from the air motor and; returning it to normal under the action of the spring l9, and the damper 2 is thus permitted to close'under the action" of gravity.

It is, of course, to be" understood that many variations may be made in the details of construction of the several instrumentalities illustrated and described in the above specification, without departing from" the spirit of my invention as outlined in the appended claims. 7

Though the several instruments are shown as distinct"s'tr1ioture's,it is to be understood that they may be redesigned and incorporated in a single structure, the instruments shown and described being composed of several agencies at prese t in 'use and modified. to accomplish the 'en'dsoi V [invention V Having,"therefore, described my invention, What I claim and desire to secure by Letters Pat "ratus toiopen said leakage orifice when thepressure reaches a predetermined normal in the pressure sensitive' apparatus. 7 v

2 In boiler-pressure control apparatus including a fire control means; a boiler pressuresensitive apparatus; an air motor" connected, to'said fire controlmeans and adapted to operate to increase the fire when compressed air is admitted th'retoian air control apparatus connected betweenthe source of air pressureahd said air mo tor, "said air control apparatus being"pro'vided with anair leakage'orifice; and a'pivoted finger adapted to normally close said leakage orifice, butf adapted tobe engaged bysaid pressure-sensitive'apparatus to opensa'id leakage orifie'e when the pressure' reaches a predetermined normal in the pressure-sensitiveapparatus. 1 JESSEB. SNYDER. 

